Basement Wall Waterproofer Review: Super Thoroseal
Two years ago, we waterproofed over 1000 square feet of cinder block wall in our mostly-underground basement. We applied Super Thoroseal to 500 sq. ft., and SunnyDry Foundation Waterproofer to the other 500 sq. ft. (Follow that SunnyDry link for our initial review of their product, which is still holding up well today).
When we ran that initial review, we promised a follow-on article with a review of Super Thoroseal’s performance, but like so many things, it fell off the plate. So here’s that review, two years later.
What is Super Thoroseal?
To bring you back up to speed, Super Thoroseal is a portland-cement based waterproofer that is sold in 35 lb., five gallon buckets at a variety of stores–most notably Home Depot, where we purchased it. Super Thoroseal is suitable for a variety of waterproofing applications, including above and below grade concrete and masonry waterproofing. It cannot be applied to painted surfaces.
Super Thoroseal claims a 200 PSI waterproofing capability, nearly 10 times the standard waterproofing available from paint-based solutions like traditional Dry Lok. (Note: Dry Lok now offers a portland cement based solution as well).
Installation method is extremely important as the product will not work as advertised if the instructions for wall prep and application are not followed to a “T”. I’ll repeat this because it’s important: installation method is very important. Do not short cut the installation or your seal may fail prematurely. Alright, enough of that. Here’s how to apply it:
How to Apply Super Thoroseal
Wall Prep: The walls must be cleaned of debris and efflorescence, wet (as in, with a hose), and the temperature must be above 40 degrees. You can see Thoro’s online instructions & product sheet for more information on application specs and performance.
Mixing: Measure and add the appropriate amount of water to a separate five-gallon bucket. Do not add too much or too little water. Add the Super Thoroseal powder and mix with a suitable drill & mixing paddle until it becomes a pancake batter consistency. Do not try to mix Super Thoroseal by hand, you will not be able to get a good mix. Super Thoroseal stays spreadable for about 30 minutes. Do not pour water into the Super Thoroseal bucket. The water must be poured into a separate bucket and the powder dumped on top!
Application: Wet the walls with a garden hose and apply the mixed batter using a tampico fiber brush (also available at the big box). Cover the walls thoroughly. Full seal occurs after two coats. Note: you must apply both coats within a 24-48 hour period. Do not let the first coat stand for more than 48 hours or the second coat will not bond and seal well.
Super Thoroseal Coverage & Price
One five-gallon bucket runs about $25 at the local big box. Coverage is up to 105 sq. ft. and requires two coats to achieve watertight seal. We found Thoro’s coverage claims on the bucket to be accurate.
Super Thoroseal Water Sealing Performance
We’re pleased to report that after two years, Super Thoroseal is living up to its promise. We have no leaks in the basement, and recommend this product to folks looking to seal their own basements. If we ever do experience an issue, we’ll update this article with the bad news.
Update 10/16/09: Last night, we examined the wall in one of the corner areas on the wall and noticed a small section (about 2×2 inches) of the ST had de-laminated from the wall. It appeared that the Super Thoroseal in this area didn’t form a good bond and was a bit ‘powdery’ – it wasn’t well mixed. I don’t blame this on ST and actually believe it may have been an error in our installation process (the first coat we applied didn’t follow my instructions here exactly, and we may not have mixed it well because it was our first try). The good news is the issue appears isolated and not characteristic of the rest of the wall. Also, there’s still no moisture in the area despite the rain we’ve had, which leads me to believe some of the ST is still clogging the pours of the concrete. I will continue to update this post if we have any other issues.
What do you think? Do you have any experience with Super Thoroseal? Leave your thoughts in the comments section.
P.S. There’s been a lot of news lately about changes to FTC regulations that require bloggers to disclose any form of compensation they receive for reviewing products. Just so you know our policy: we always let you know if a company gives us a product (vs. one that we bought off the shelf and reviewed on our own). If we don’t mention that a product was provided to us, it means that we bought the product with our own cash (as is the case in this review of Super Thoroseal).
Comments & Conversation on this Article...
13 Responses to Basement Wall Waterproofer Review: Super Thoroseal
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October 6th, 2009 12:43 pm
Wow, this review was so educational! I had no idea where to even begin with the process of using a waterproofer. Sadly, I don’t think this will work for my basement. But I’m enjoying learning about what’s available. Thanks for the great article!
October 6th, 2009 9:39 pm
Kelli, glad you enjoyed it! We’re very pleased with Thoro’s product…
October 15th, 2009 4:48 pm
Great information. Thanks for the review! I was skeptic of using Super Thoroseal ($25 x pail) because the price difference between this product and Drylok ($100 x pail). I just applied the second coat and hope; as you, state that it works great!
Thanks again,
October 16th, 2009 11:29 pm
H – We’re still happy with the product. I will say that in one 2 inch by 2 inch area on the basement wall we recently had a piece delaminate. Now, that’s not characteristic and when we applied the Super Thoroseal, we didn’t follow my instructions here 100% …
In fact, we applied the first coat and then let it sit for a week. We then applied two more coats. We still aren’t getting moisture in that location, I suspect because the ST seeped into the pours of the concrete.
I think you’re real safe going with ST vs. Drylok — The Drylok product that is in the same size barrell gets a little more coverage, but doesn’t seal as tight as ST… Just make sure to follow the instructions. We’ve talked to a number of local contractors and they trust ST for this type of sealing job.
October 17th, 2009 11:27 pm
Wow! Love the article. Hubby and I have a huge two stall commercial truck garage on our property and have been debating if we should attempt to build a home out of it. One of our main concerns is that when the garage was built 30-35 years ago, the previous owners did not lay any type of moisture barrier before pouring it’s concrete floor. The drainage is awful and the floor is always wet. Two rooms were built into the back of the garage and they are full of mold. (as I’m sure the trusses and rafters are also). This garage is 32′ x 48′ with 12′ ceilings… This (in my humble opinion) would make a great start for a house!
Thanks for the review!!!
Tammy OHagan
November 12th, 2009 11:19 pm
Thanks for taking the time to post such valuable information. We, too, are preparing to seal a block wall and found your advice to be most helpful. I notice that with most of these products, there is a need to remove any efflorescence. Did you have to do that, and if so, how did you do it? We’ve seen a variety of conflicting advice on the subject.
January 19th, 2010 7:33 pm
RE: Basement Wall Waterproofer Review: Super Thoroseal
Hello,
Loved the review on the Thoroseal and SunnyDry waterproofing. How is the SunnyDry holding up after 2 years?
Thanks!
January 19th, 2010 11:49 pm
Hi TIm,
SunnyDry is also performing well.
In November, we had the walls insulated with closed cell foam, permanently closing up our work, so it will be hard for me to monitor further progress unless something really goes wrong (which I certainly hope it doesn’t).
Can’t say it enough – prep instructions are important.
January 23rd, 2010 10:26 am
Any advice on basement floor sealer. Will this work on the floor as well?
Cole
January 31st, 2010 9:36 pm
Cole, this won’t work for basement floors… Unfortunately, I don’t know a good product for that. Have you looked at something like Schluter’s Ditra? What are you planning for a final walking surface?
February 6th, 2010 5:11 pm
i have cut back the existing plaster and render back to the brick/cement block. Should I apply the Thoroseal onto the brick/cement block or between coats of new render? and what plaster finish should I use
February 8th, 2010 12:11 am
Derek,
ST should be applied directly to the cement/brick. Note that you can’t apply anything directly to the ST after you waterseal with it (e.g., no painting, plaster, etc). You will have to frame out a finished wall.
Fred
February 11th, 2010 11:39 am
My question is i did not see on the instructions for ST you had to apply second coat within 48 hours. I have first on so far concrete wall but its close to being 48 hours and plus. Is this going to be worth putting/attempting second coat of ST or is there an other product to put over ST for a second coat? Please Advise
Thank you
Lou..